US-12626902-B2 - Electrode for rechargeable lithium battery, electrode assembly and rechargeable lithium battery including the same

US12626902B2US 12626902 B2US12626902 B2US 12626902B2US-12626902-B2

Abstract

An electrode for a rechargeable lithium battery includes: a current collector, one surface of the current collector being partitioned into a first region and a second region spaced apart from the first region; a safety functional layer on the first region; an active material layer on the first region, the safety functional layer being between the current collector and the active material layer; and an insulating layer on the second region. A length of the safety functional layer is longer than that of the active material layer, and the electrode satisfies Equation 1: a>b Equation 1 in which a is a separation distance between the active material layer and the insulating layer, and b is a separation distance between the safety functional layer and the insulating layer.

Inventors

Jaehwan HA
TAEJOONG KIM
Suhyun KIM
Seok Gyun PARK
Hyunhee KIM
Hoyong AN
HeeEun YOO
Duckhyun Kim

Assignees

SAMSUNG SDI CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20230621
Priority Date: 20220708

Claims (20)

1 . An electrode for a rechargeable lithium battery, comprising a current collector, a safety functional layer, an active material layer, and an insulating layer; wherein one surface of the current collector is partitioned into a first region and a second region spaced apart from the first region; the safety functional layer and the active material layer are sequentially stacked on the first region, and a length of the safety functional layer is longer than that of the active material layer; the insulating layer is disposed on the second region; and the electrode satisfies Equation 1: a>b [Equation 1] wherein, in Equation 1, a is a first distance, and a separation distance between the active material layer and the insulating layer; and b is a second distance, and is a separation distance between the safety functional layer and the insulating layer.
2 . The electrode for a rechargeable lithium battery of claim 1 , wherein the electrode satisfies Equation 2: 1 mm≤( a - b )≤5 mm [Equation 2] wherein, in Equation 2, definitions of a and b are the same as in claim 1 .
3 . The electrode for a rechargeable lithium battery of claim 1 , wherein the electrode satisfies Equation 3: 1 mm≤ a≤ 11 mm [Equation 3] wherein, in Equation 3, the definition of a is the same as in claim 1 .
4 . The electrode for a rechargeable lithium battery of claim 1 , wherein the electrode satisfies Equation 4: 0 mm≤ b≤ 6 mm [Equation 4] wherein, in Equation 4, the definition of b is the same as in claim 1 .
5 . The electrode for a rechargeable lithium battery of claim 1 , wherein the safety functional layer, the active material layer and the insulating layer each independently gradually decrease in area from the inner side adjacent to the current collector toward the outer side.
6 . The electrode for a rechargeable lithium battery of claim 5 , wherein the safety functional layer and the active material layer each independently have an inclined surface in which an end portion adjacent to the insulating layer is inclined toward an outer surface from an inner surface adjacent to the current collector.
7 . The electrode for a rechargeable lithium battery of claim 5 , wherein the insulating layer has an inclined surface that an end portion adjacent to the safety functional layer and the active material layer is inclined toward an outer surface from an inner surface adjacent to the current collector.
8 . The electrode for a rechargeable lithium battery of claim 1 , wherein the safety functional layer, the active material layer, and the insulating layer each independently have a thickness of about 0.1 to about 100 μm.
9 . The electrode for a rechargeable lithium battery of claim 1 , wherein the safety functional layer includes lithium transition metal phosphate.
10 . The electrode for a rechargeable lithium battery of claim 9 , wherein the safety functional layer further includes a first binder and a first conductive material.
11 . The electrode for a rechargeable lithium battery of claim 1 , wherein the insulating layer includes a ceramic.
12 . The electrode for a rechargeable lithium battery of claim 1 , wherein the electrode is a positive electrode, and the active material layer includes a positive electrode active material.
13 . The electrode for a rechargeable lithium battery of claim 1 , wherein the active material layer further includes a second binder and a second conductive material.
14 . An electrode assembly for a rechargeable lithium battery being a winding-type electrode assembly comprising a stack in which a negative electrode, a separator, and a positive electrode are sequentially stacked, and the stack is wound; wherein any one electrode of the negative electrode and the positive electrode includes a current collector, a safety functional layer, an active material layer, and an insulating layer; one surface of the current collector is partitioned into a first region and a second region spaced apart from the first region; the safety functional layer and the active material layer are sequentially stacked on the first region, and a length of the safety functional layer is longer than that of the active material layer; the insulating layer is disposed on the second region; and the electrode satisfies Equation 1: a>b [Equation 1] wherein, in Equation 1, a is a first distance, and a separation distance between the active material layer and the insulating layer; and b is a second distance, and is a separation distance between the safety functional layer and the insulating layer.
15 . The electrode assembly for a rechargeable lithium battery of claim 14 , wherein the winding-type electrode assembly is pressed in a vertical direction in a state in which the stack is wound, so as to include a first flat portion and a second flat portion extending parallel to each other and a first curved portion and a second curved portion connecting both sides of the first and second flat portions, respectively, and the safety functional layer is disposed on the first curved portion, the second curved portion, or both.
16 . The electrode assembly for a rechargeable lithium battery of claim 15 , wherein the electrode assembly satisfies Equation 5: 1.0 mm≤ a≤{D*Π/ 2)} mm [Equation 5] wherein, in Equation 5, a is a first distance, and a separation distance between the active material layer and the insulating layer, and D is a thickness of the winding-type electrode assembly and is the distance between the first flat portion and the second flat portion.
17 . The electrode assembly for a rechargeable lithium battery of claim 15 , wherein the electrode assembly satisfies Equation 6: 0 mm ≤ b≤{D *(Π/2)−4} mm [Equation 6] wherein, in Equation 6, b is a second distance, and is a separation distance between the safety functional layer and the insulating lay; and D is a thickness of the winding-type electrode assembly and is the distance between the first flat portion and the second flat portion.
18 . The electrode assembly for a rechargeable lithium battery of claim 16 or claim 17 , wherein D is about 1.5 to about 50 mm.
19 . The electrode assembly for a rechargeable lithium battery of claim 14 , wherein the electrode including the current collector, the safety functional layer, the active material layer and the insulating layer is the positive electrode.
20 . A rechargeable lithium battery comprising the electrode assembly of claim 14 and an electrolyte.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to and the benefit of Korean Patent Application No. 10-2022-0084661, filed in the Korean Intellectual Property Office on Jul. 8, 2022, the entire content of which is incorporated herein by reference. BACKGROUND 1. Field Embodiments relate to an electrode for a rechargeable lithium battery, an electrode assembly including the same, and a rechargeable lithium battery including the same. 2. Description of the Related Art A portable information device, such as a cell phone, a laptop, smart phone, and the like, or an electric vehicle uses a rechargeable lithium battery having high energy density and easy portability as a driving power source. Recently, research has been actively conducted to use a rechargeable lithium battery with high energy density as a driving power source or power storage power source for hybrid or electric vehicles. However, it is difficult to provide sufficient safety and reliability while reducing or minimizing the decrease in energy density during driving of a rechargeable lithium battery having high energy density. SUMMARY Embodiments of the present disclosure provide an electrode for a rechargeable lithium battery, an electrode assembly including the same, and a rechargeable lithium battery including the same, which are capable of securing (or providing) safety and reliability while reducing or minimizing a decrease in energy density during driving of a rechargeable lithium battery having high energy density. In an embodiment, an electrode for a rechargeable lithium battery includes a current collector, a safety functional layer, an active material layer, and an insulating layer. One surface of the current collector is partitioned into a first region and a second region spaced apart from the first region. The safety functional layer and the active material layer are sequentially stacked on the first region, and the insulating layer is on the second region. A length of the safety functional layer is longer than that of the active material layer, and the electrode satisfies Equation 1: a>b Equation 1 in which a is a first distance and a separation distance between the active material layer and the insulating layer, and b is a second distance and is a separation distance between the safety functional layer and the insulating layer. Another embodiment includes an electrode assembly for a rechargeable lithium battery in which the above-described electrode is any one of a negative electrode and a positive electrode. Another embodiment includes a rechargeable lithium battery including the above-described electrode assembly and an electrolyte. The electrode for a rechargeable lithium battery according to an embodiment, an electrode assembly including the same, and a rechargeable lithium battery may ensure safety and reliability while reducing or minimizing energy density reduction during driving. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are schematic diagrams showing an electrode according to embodiments. FIG. 3 is a schematic view showing an electrode assembly according to an embodiment. FIG. 4 schematically illustrates a rechargeable lithium battery according to an embodiment. FIG. 5 is an image of a negative electrode of Comparative Example 1 after cycle-life evaluation. FIG. 6 is a SEM image of the negative electrode of Comparative Example 1 after cycle-life evaluation. DETAILED DESCRIPTION Hereinafter, embodiments of the present disclosure will be described, in detail, so that those of ordinary skill in the art can easily implement them. However, the present disclosure may be embodied in many different forms and should not be construed as being limited to the embodiments described herein. It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it may be directly on, connected, or coupled to the other element or layer or one or more intervening elements or layers may also be present. When an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. For example, when a first element is described as being “coupled” or “connected” to a second element, the first element may be directly coupled or connected to the second element or the first element may be indirectly coupled or connected to the second element via one or more intervening elements. In the figures, dimensions of the various elements, layers, etc. may be exaggerated for clarity of illustration. The same reference numerals designate the same elements. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Further, the use of “may” when describing embodiments of the present disclosure relates to “one or more embodiments of the present disclosure.” Expressions, such as “at least one of” a